9-dars: Struct (tuzilma)

Dars haqida

Davomiyligi: 90 daqiqa Maqsad: Talaba struct (tuzilma) ni bilishi, foydalanishi, struct array va struct funksiyalar bilan ishlay olishi kerak.

1. Struct nima?

Struct — bir nechta turli maydonlarni bitta nom ostida birlashtirish.

struct Talaba {
    char name[50];
    int age;
    double score;
};

Talaba — name, age, score to'plami.

2. Nima uchun struct?

Struct'siz:

char name[50];
int age;
double score;

// Yana bir talaba?
char name2[50];
int age2;
double score2;

// 100 ta talaba — uzoq!

Struct bilan:

struct Talaba {
    char name[50];
    int age;
    double score;
};

struct Talaba akmal;
struct Talaba aziza;

struct Talaba talabalar[100];  // 100 ta talaba

3. Struct e'lon qilish

// Variant 1: alohida
struct Point {
    int x;
    int y;
};

struct Point p1;

// Variant 2: e'lon va o'zgaruvchi birga
struct Point {
    int x;
    int y;
} p1, p2;

// Variant 3: typedef bilan (`struct` yozish kerak emas)
typedef struct {
    int x;
    int y;
} Point;

Point p1;  // `struct` kerak emas

typedef

typedef — eng keng tarqalgan yondashuv. Kod toza ko'rinadi.

4. Maydonlarga kirish

. (dot) operator:

typedef struct {
    char name[50];
    int age;
    double score;
} Talaba;

Talaba a;
strcpy(a.name, "Akmal");
a.age = 22;
a.score = 95.5;

printf("Ism: %s\n", a.name);
printf("Yosh: %d\n", a.age);
printf("Ball: %.1f\n", a.score);

5. Initialize

Talaba a = {"Akmal", 22, 95.5};

// Yoki nomli (C99+):
Talaba b = {.name = "Aziza", .age = 19, .score = 92.0};

6. Struct nusxalash

C'da struct'ni to'g'ridan-to'g'ri nusxalash mumkin:

Talaba a = {"Akmal", 22, 95.5};
Talaba b = a;  // OK, butun struct nusxalanadi

b.score = 80.0;
printf("%.1f\n", a.score);  // 95.5 (o'zgarmadi)

(Massivlar bilan bunday emas — alohida.)

7. Struct array

Talaba talabalar[3] = {
    {"Akmal", 22, 95.5},
    {"Aziza", 19, 92.0},
    {"Botir", 25, 78.5}
};

for (int i = 0; i < 3; i++) {
    printf("%s (yosh: %d, ball: %.1f)\n",
           talabalar[i].name,
           talabalar[i].age,
           talabalar[i].score);
}

8. Struct va funksiyalar

Pass by value (nusxa)

void print(Talaba t) {
    printf("%s, %d, %.1f\n", t.name, t.age, t.score);
}

int main(void) {
    Talaba a = {"Akmal", 22, 95.5};
    print(a);  // nusxa uzatiladi
    return 0;
}

Pass by pointer (manzil)

void print(const Talaba *t) {
    printf("%s, %d, %.1f\n", t->name, t->age, t->score);
}

int main(void) {
    Talaba a = {"Akmal", 22, 95.5};
    print(&a);
    return 0;
}

-> operator

Pointer orqali maydonga kirish:

t->name    ekvivalent: (*t).name

Struct juda katta bo'lsa — pointer orqali uzatish tezroq.

9. Struct return

Talaba create_student(const char *name, int age) {
    Talaba t;
    strcpy(t.name, name);
    t.age = age;
    t.score = 0;
    return t;  // butun struct qaytariladi
}

10. Nested struct

Struct ichida struct:

typedef struct {
    int day;
    int month;
    int year;
} Date;

typedef struct {
    char name[50];
    Date birthday;
} Person;

Person p;
strcpy(p.name, "Akmal");
p.birthday.day = 15;
p.birthday.month = 5;
p.birthday.year = 1995;

11. Struct va malloc

Talaba *t = malloc(sizeof(Talaba));
strcpy(t->name, "Akmal");
t->age = 22;
t->score = 95.5;

free(t);

Dinamik massiv:

int n = 100;
Talaba *students = malloc(n * sizeof(Talaba));

for (int i = 0; i < n; i++) {
    sprintf(students[i].name, "Talaba_%d", i);
    students[i].age = 18 + i % 10;
    students[i].score = 50 + i;
}

free(students);

12. To'liq misol: Talabalar bazasi

#include <stdio.h>
#include <string.h>

typedef struct {
    char name[50];
    int age;
    double score;
} Talaba;

void print_student(const Talaba *t) {
    printf("Ism: %-15s Yosh: %d  Ball: %.1f\n", t->name, t->age, t->score);
}

double average_score(const Talaba *talabalar, int n) {
    double sum = 0;
    for (int i = 0; i < n; i++) {
        sum += talabalar[i].score;
    }
    return sum / n;
}

int find_max(const Talaba *talabalar, int n) {
    int max_idx = 0;
    for (int i = 1; i < n; i++) {
        if (talabalar[i].score > talabalar[max_idx].score) {
            max_idx = i;
        }
    }
    return max_idx;
}

int main(void) {
    Talaba talabalar[5] = {
        {"Akmal", 22, 95.5},
        {"Aziza", 19, 92.0},
        {"Botir", 25, 78.5},
        {"Dilshod", 21, 88.0},
        {"Eldor", 20, 65.5}
    };
    int n = 5;
    
    printf("=== TALABALAR ===\n");
    for (int i = 0; i < n; i++) {
        print_student(&talabalar[i]);
    }
    
    printf("\nO'rtacha: %.2f\n", average_score(talabalar, n));
    
    int max_idx = find_max(talabalar, n);
    printf("Eng yuqori: %s (%.1f)\n", 
           talabalar[max_idx].name, 
           talabalar[max_idx].score);
    
    return 0;
}

13. Struct sort

void sort_by_score(Talaba *talabalar, int n) {
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j < n - 1 - i; j++) {
            if (talabalar[j].score < talabalar[j+1].score) {
                Talaba temp = talabalar[j];
                talabalar[j] = talabalar[j+1];
                talabalar[j+1] = temp;
            }
        }
    }
}

14. Misol: Geometriya

typedef struct {
    double x;
    double y;
} Point;

typedef struct {
    Point center;
    double radius;
} Circle;

typedef struct {
    Point p1;
    Point p2;
} Line;

double distance(Point a, Point b) {
    double dx = a.x - b.x;
    double dy = a.y - b.y;
    return sqrt(dx*dx + dy*dy);  // math.h kerak
}

double circle_area(Circle c) {
    return 3.14159 * c.radius * c.radius;
}

15. Bit fields

Maxsus — bit darajasidagi struct:

struct Flags {
    unsigned int is_active : 1;   // 1 bit
    unsigned int priority : 3;    // 3 bit (0-7)
    unsigned int category : 4;    // 4 bit (0-15)
};

Foydalanish — kam, tizim dasturlashda.

16. Union (qisqacha)

Struct'ga o'xshash, lekin bir vaqtda faqat bitta maydon.

union Value {
    int i;
    float f;
    char s[20];
};

union Value v;
v.i = 42;
// yoki
v.f = 3.14;
// yoki
strcpy(v.s, "Hello");

Hajmi — eng katta maydon.

Foydalanish — kam.

17. Enum (qisqacha)

Enum — nomli konstantalar:

typedef enum {
    SUNDAY,
    MONDAY,
    TUESDAY,
    WEDNESDAY,
    THURSDAY,
    FRIDAY,
    SATURDAY
} Day;

Day today = MONDAY;

switch (today) {
    case MONDAY: printf("Dushanba\n"); break;
    case TUESDAY: printf("Seshanba\n"); break;
    // ...
}

Aslida 0, 1, 2, ... bilan saqlanadi.

18. Memory alignment

typedef struct {
    char c;     // 1 bayt
    int i;      // 4 bayt
    char c2;    // 1 bayt
} Test;

printf("%zu\n", sizeof(Test));  // 12 (alignment uchun)

C alignment uchun bo'sh joy qoldiradi (tezlik uchun).

Maydonlarni kattadan kichikga tartiblash — hajmni kamaytiradi:

typedef struct {
    int i;      // 4
    char c;     // 1
    char c2;    // 1
} Better;       // 8 byte

Darsdagi topshiriqlar

1 — Birinchi struct

first-struct.c — Talaba struct yarating va bitta talaba ma'lumotini chiqaring.

2 — Struct array

students.c — Dars matnidagi to'liq talabalar bazasi.

3 — Struct sort

sort-students.c:

Ball bo'yicha sort (descending)
Ism bo'yicha sort (alphabetic)
Yosh bo'yicha sort

4 — Geometry

geometry.c — Point, Circle, Line struct'lari.

Funksiyalar:

distance(Point a, Point b)
circle_area(Circle c)
circle_perimeter(Circle c)
line_length(Line l)
is_inside(Point p, Circle c) — point doirada bormi?

5 — Mahsulot inventari

inventory.c:

typedef struct {
    char name[50];
    double price;
    int quantity;
} Product;

10 ta mahsulot
Jami qiymat
Eng arzon
Eng qimmat
Mahsulot qidirish (nom bo'yicha)

6 — Nested struct

nested.c — Date va Person struct'lari.

Person p = {"Akmal", {15, 5, 1995}};
printf("%s tug'ilgan: %d.%d.%d\n", p.name, 
       p.birthday.day, p.birthday.month, p.birthday.year);

7 — Dinamik struct

dynamic.c:

Foydalanuvchi N kiritsin, keyin N ta talaba ma'lumotini olib statistika chiqarish.

8 — Library

library.c — kichik kutubxona:

typedef struct {
    char title[100];
    char author[50];
    int year;
    int available;  // 1 — bor, 0 — yo'q
} Book;

Book library[100];
int book_count = 0;

void add_book(const char *title, const char *author, int year);
void show_books(void);
void borrow_book(const char *title);
void return_book(const char *title);
Book *find_book(const char *title);

9 — Bank account

account.c:

typedef struct {
    int id;
    char owner[50];
    double balance;
} Account;

void deposit(Account *acc, double amount);
void withdraw(Account *acc, double amount);
void transfer(Account *from, Account *to, double amount);
void show_account(const Account *acc);

10 — GitHub

bash

$ mkdir 5-oy-dars-9
$ git add . && git commit -m "feat: dars 9 - structs" && git push

Lug'at

Termin	Izoh
struct	Tuzilma — maydonlar to'plami
typedef	Tur uchun alias
Field / Member	Maydon
Dot operator (`.`)	Maydonga kirish
Arrow operator (`->`)	Pointer orqali maydon
Nested struct	Struct ichida struct
Union	Bir vaqtda bitta maydon
Enum	Nomli konstantalar
Memory alignment	Xotirada tekislash
Pass by value	Nusxa uzatish
Pass by pointer	Manzil uzatish

Keyingi dars

10-dars: File I/O →

9-dars: Struct (tuzilma) ​

1. Struct nima? ​

2. Nima uchun struct? ​

3. Struct e'lon qilish ​

4. Maydonlarga kirish ​

5. Initialize ​

6. Struct nusxalash ​

7. Struct array ​

8. Struct va funksiyalar ​

Pass by value (nusxa) ​

Pass by pointer (manzil) ​

9. Struct return ​

10. Nested struct ​

11. Struct va malloc ​

12. To'liq misol: Talabalar bazasi ​

13. Struct sort ​

14. Misol: Geometriya ​

15. Bit fields ​

16. Union (qisqacha) ​

17. Enum (qisqacha) ​

18. Memory alignment ​

Darsdagi topshiriqlar ​

Lug'at ​

Keyingi dars ​